Various types of memory devices store data in two-dimensional or three-dimensional arrays of memory cells. Physical and/or electrical properties of the memory cells may be altered to write data, and sensed to read data. For example, in a two-dimensional array where word lines are coupled to rows of cells and bit lines are coupled to columns of cells, reading data from a cell may involve applying a read voltage to a word line, and sensing a current or voltage at a bit line, to determine the state of a cell. However, a bit line voltage or current may also be affected by “sneak current” through other cells in the array. Sneak current may disturb data in neighboring cells during a write operation, reduce the reliability of read operations, and increase the overall power consumption (and heat generation) of a memory device. Accordingly, certain memory devices may include switching or selection components such as transistors, Zener diodes, or the like, which limit leakage current through unselected cells. For a three-dimensional array, however, providing selection components for multiple layers of memory cells may significantly increase the time and cost of fabrication.